"Milk teeth," the temporary teeth that are lost to make way for the permanent teeth.

DEFINITIVE HOST:

Host in or on which a parasite reaches sexual maturity or undergoes sexual reproduction.

DEGENERATIVE JOINT DISEASE:

Term for a group of disorders resulting in progressive deterioration of the articular cartilage of a joint, accompanied by bone proliferation around the joint margins and thickening of the soft tissues of the joint; also called degenerative arthritis.

DEGRANULATION:

Release of granules from a cell.

DEHISCENCE:

Breakdown of healing at a wound or suture site.

DEHYDRATION:

Loss of body water, occurring when the intake of water is insufficient to cover water losses.

Short threadlike extensions of a nerve cell; they act to receive nerve impulses from adjacent nerve cells.

DENSITY:

The concentration of a nutrient in a feed.

DENTAL FLOAT:

Veterinary instrument for grinding down enamel points.

DENTIN:

The tooth layer lying between the inner pulp (containing the tooth's blood and nerve supply) and the overlying enamel.

DEOXYGENATED:

Having a low oxygen content; said of venous blood.

DEOXYRIBONUCLEIC ACID (DNA):

The genetic material of living cellular organisms and of certain viruses.

DEPIGMENTATION:

Localized loss of normal skin color.

DEPOLARIZATION:

A change from a negative to a positive charge, generating an electrical wave (as in the production of the heartbeat).

DERMAL PAPILLA:

Structure at the base of each hair follicle that, with the associated hair matrix cells, is responsible for the production of hair.

DERMATITIS:

Any inflammatory skin disease.

DERMATOMYCOSIS:

Any fungal skin infection.

DERMATOPHILOSIS:

Relatively sporadic skin disease caused by an unusual threadlike bacterium, Dermatophilus congolensis; also known as streptothricosis and rain-scald.

DERMATOPHYTES:

Fungi causing ringworm.

DERMATOPHYTOSIS:

Ringworm.

DERMATOSIS:

Any skin disease, particularly one without an inflammatory component.

DERMIS:

The middle and thickest major layer of the skin; composed of connective tissue fibers and a ground substance, it lies just beneath the epidermis, the outermost layer of the skin.

DERMOID:

A misplaced piece of skin found on the conjunctiva as a congenital lesion; it may also involve the cornea.

DESMITIS:

Inflammation of a ligament.

DETOXIFICATION:

Reduction in toxic properties of compounds.

DETRUSOR:

Smooth muscle layer of the bladder wall; contraction of the detrusor results in voiding of urine.

DEXTROSE:

Glucose; blood sugar.

DIABETES MELLITUS:

Diabetes, a chronic disease caused by either insufficient production of insulin by the islets of Langerhans in the pancreas, or by resistance of target tissues to the effects of insulin. Diabetes results in an inability of cells to utilize glucose (blood sugar), with widespread adverse effects owing to impaired utilization of carbohydrates, fats, and proteins by the body.

DIABETIC KETOACIDOSIS:

Serious, life-threatening complication of untreated or poorly treated diabetes mellitus, characterized by the buildup of ketone bodies in the circulation and a fall in blood pH, i.e., increasing acidity of the blood.

DIAPHRAGM:

The large muscle used for breathing which separates the abdominal and chest cavities.

DIAPHRAGMATIC HERNIA:

Rupture of the diaphragm, with movement of some of the abdominal contents into the chest cavity.

DIAPHYSIS:

The central shaft of a long bone.

DIARRHEA:

An increase in the fluid content, volume, or frequency of bowel movements.

DIASTOLE:

The relaxation/filling phase of the heartbeat, following systole.

DIASTOLIC BLOOD PRESSURE:

The pressure that occurs when the heart is not pumping blood into the arterial system (i.e., during the relaxation period between contractions).

DIASTOLIC HEART MURMUR:

Murmur that is present only during diastole (the relaxation phase of the heartbeat).

DIESTRUS:

The quiescent period between one estrus period and the next; also called interestrus.

DIFFERENTIAL WHITE BLOOD CELL COUNT:

Total white blood cell (WBC) counts and percentages of different WBC types present; component part of a complete blood count (CBC).

DIFFERENTIATION:

The development of cellular specialization as cells mature.

DIGESTIBLE CARBOHYDRATES:

Sugars and starches.

DIGESTIBLE ENERGY (DE):

For a feed, the sum of the digestible carbohydrate, protein, fat, and fiber; also called total digestible nutrients (TDN).

DIGESTION:

The breakdown of larger substances into smaller subunits, which can be more readily carried into the body for use in energy production and the construction of body tissues.

DIGITAL PRESSURE:

Pressure applied by the fingers.

DIGITAL PULSE:

The pulse as felt in the digital arteries of the feet; important for the detection of laminitis (founder).

DIGOXIN:

Medication that increases the strength of the heartbeat while decreasing the heart rate; used most often for the treatment of congestive heart failure.

DILATED:

Enlarged or widened; expanded.

DILATED FIXED PUPIL:

Pupil that does not contract.

DILATION:

Expansion.

DIRECT LIFE CYCLE:

With regard to parasites, a life cycle that can be completed without the participation of an intermediate host.

DISCOSPONDYLITIS:

Inflammation of an intervertebral disk.

DISPENSABLE AMINO ACIDS:

Amino acids that can be synthesized by the body so long as a source of nitrogen is present in the diet.

DISSEMINATED INTRAVASCULAR COAGULATION (DIC):

A bleeding disorder characterized by the excessive utilization of blood-clotting factors, due to widespread clotting within blood vessels; the resultant hemorrhaging often represents a terminal event in a number of diseases.

DISTAL:

Farther, more distant.

DISTEMPER:

Alternative name for strangles.

DISUSE ATROPHY:

Loss of muscle mass because of muscle disuse.

DIURETIC:

Any drug that promotes urination.

DIURNAL:

Having a daily cycle or rhythm.

DNA:

Deoxyribonucleic acid, the genetic material of living cellular organisms and of certain viruses.

DOMINANT GENE:

A gene capable of expressing its trait even when carried by only one member of a chromosome pair.

DOPPLER ECHOCARDIOGRAPHY:

Technique using sound waves to examine the direction and velocity of blood flow within the heart and great vessels.

DORSAL:

Pertaining to the back; toward the back.

DUCT:

Tiny tube or passageway.

DUCTUS ARTERIOSUS:

Blood vessel normally present during fetal life that allows blood to bypass the lungs, which of course are nonfunctional at this time; the ductus normally closes shortly after birth.

DUODENUM:

The first part of the small intestine, connecting the stomach with the jejunum.